Lean manufacturing glossary

1-1-90 method

The 1-1-90 method is a way to roll out continuous improvement: start with 1 area and 1 pain point, run it for 90 days with a team, then expand what worked to the next areas and plants. It was named by Angad Singh and the LeanSuite team for the way they already work with manufacturers, and it is a general approach that needs no particular software. At day 90 the team decides whether to expand, run another round or stop.

Related: Model line, Yokoten, Kaizen, PDCA (Plan-Do-Check-Act), Standard work

5 Whys

The 5 Whys is a root cause analysis technique that asks “why?” repeatedly, with each answer becoming the next question, until the team reaches a cause it can act on. Five is a rule of thumb, not a fixed count. It works best on problems with a single chain of cause and effect, and each answer should be checked against facts at the gemba rather than guessed in a meeting room.

Related: Root cause analysis (RCA), Fishbone diagram

5G methodology

The 5G methodology is a problem investigation discipline that confirms five things before anyone proposes a cause: gemba (the actual place), gembutsu (the actual thing), genjitsu (the actual facts), genri (the principles that apply), and gensoku (the standard the process should follow). The first three are gathered by going to see; the last two compare what was found with how the process is supposed to work. It keeps root cause analysis grounded in evidence rather than opinion.

Related: Genchi genbutsu, Gemba, 5W1H, Root cause analysis (RCA)

5S

5S is a workplace organization method with five steps: Sort, Set in order, Shine, Standardize, and Sustain. Teams remove what is not needed, give everything a marked place, clean and inspect, write the standard down, and audit it so the area stays that way. A well-run 5S area makes abnormalities, missing tools, and safety hazards obvious at a glance.

Related: Visual management, Standard work, Red tagging, 5S audit, Shadow board

5S audit

A 5S audit is a regular, scored check of a work area against its 5S standard, using a fixed checklist for each of the five S’s. It is usually done by a supervisor or a rotating auditor on a set schedule, and the score is posted in the area so the team can see its trend. Findings become actions, which is how the Sustain step is kept up rather than left to good intentions.

Related: 5S, Red tagging, Layered process audit (LPA)

5W1H

5W1H is a questioning method that describes a problem or a plan by answering six questions: who, what, where, when, why, and how. In problem solving it produces a clear, fact-based problem statement before any cause analysis starts; in planning it makes sure an action has an owner, a scope, a place, and a date. Some versions add “how much” to make 5W2H.

Related: Is/Is Not analysis, 5 Whys, Root cause analysis (RCA)

6Ms of production

The 6Ms are six categories used to sort the possible causes of a production problem: man (people), machine, method, material, measurement, and mother nature (environment). They are the usual bones of a fishbone diagram, and working through each one keeps a team from fixing only the cause it already suspects. The older five-category version, the 5Ms, leaves out mother nature.

Related: Fishbone diagram, Root cause analysis (RCA), 5 Whys

8 wastes of lean (DOWNTIME)

The eight wastes of lean are the kinds of activity that use time and resources without adding value for the customer: defects, overproduction, waiting, non-utilized talent, transportation, inventory, motion, and extra processing. The first letters spell DOWNTIME, a common way to remember them. The original Toyota Production System named seven; unused talent was added later.

Related: Muda, mura, muri, Value stream mapping (VSM), Waste walk, Value-added time

8D problem solving

8D problem solving is a team method for fixing a serious or recurring problem in eight steps, called disciplines: form the team, describe the problem, contain it, find the root cause, choose permanent corrective actions, implement and verify them, prevent recurrence, and recognize the team. It is common in automotive and supplier quality, where customers often require an 8D report in response to a complaint.

Related: Corrective and preventive action (CAPA), Root cause analysis (RCA)

A3 problem solving

A3 problem solving is a structured method that fits a whole problem on one A3-size sheet: background, current condition, goal, root cause analysis, countermeasures, and follow-up. The single page forces the team to agree on the facts and keep the story short enough for anyone to review. It follows the PDCA cycle and is often used by a leader to coach the person who owns the problem.

Related: PDCA (Plan-Do-Check-Act), Root cause analysis (RCA)

ABC analysis

ABC analysis sorts inventory items by annual usage value, the annual quantity used times the unit cost, into three classes: A, the few items that make up most of the value; B, the middle group; and C, the many low-value items. A typical result is 10 to 20 percent of the items making up 70 to 80 percent of the value. The class sets how tightly each item is controlled, for example how often it is cycle counted and how tight its count tolerance is.

Related: Cycle counting, Inventory record accuracy, Pareto analysis

Acceptance quality limit (AQL)

The acceptance quality limit (AQL), formerly called the acceptable quality level, is the worst average defect rate a sampling plan treats as acceptable over a continuing series of lots. It is one input to the ANSI/ASQ Z1.4 and ISO 2859-1 sampling tables, which use the lot size, the inspection level and the AQL to give the sample size and the accept and reject numbers. An AQL is not a promise that every lot is that good, since a lot with more defects can still pass on its sample, which is why critical characteristics are often checked on every part.

Related: Incoming inspection, Pre-shipment inspection, Supplier scorecard

Andon

Andon is a visual, and often audible, signal an operator uses to call for help when a problem occurs at a station, such as a defect, a missing part, or a machine fault. Pulling the andon brings a team leader to the spot quickly, and on many lines the line stops if the problem is not cleared within a set time. It is a core tool of jidoka: stop and fix problems where they happen instead of passing them on.

Related: Jidoka, Visual management

Autonomous maintenance

Autonomous maintenance is the TPM pillar in which machine operators take on basic equipment care: cleaning, inspecting, lubricating, tightening, and spotting abnormalities early. It is usually introduced in seven steps, starting with initial cleaning and moving toward operators managing their own equipment standards. Maintenance technicians are then freed for planned and more skilled work.

Related: Total productive maintenance (TPM), CILR (clean, inspect, lubricate, retighten)

Batch production

Batch production is making a set quantity of one product at a time, then changing the equipment over and making a set quantity of the next. It suits equipment shared by several products, but each batch waits as stock until it is used, so larger batches mean more inventory and longer lead times. In lean practice the batch size follows from the changeover time: shorter changeovers allow a shorter EPEI and smaller batches.

Related: EPEI (every part every interval), Single-minute exchange of die (SMED), One-piece flow, Work in process (WIP)

Behavior-based safety (BBS)

Behavior-based safety (BBS) is an approach to injury prevention that focuses on what people observably do at work. Trained observers watch tasks, record safe and at-risk behaviors, give immediate feedback, and use the pattern of observations to fix the conditions and systems that drive at-risk behavior. Done well, it is a conversation between peers, not a search for someone to blame.

Related: Near miss, Lockout/tagout (LOTO)

Bottleneck

A bottleneck is the step in a process with the least capacity relative to demand, so it limits the output of the whole line. Work piles up in front of it while the steps after it wait, which is the usual way to spot one on the floor. An hour lost at the bottleneck is an hour lost for the whole system, so, as the theory of constraints teaches, improvement there pays back most.

Related: Theory of constraints (TOC), Throughput, Line balancing, Cycle time, Work in process (WIP)

Bowling chart

A bowling chart is the monthly scorecard of a hoshin kanri plan: one row per metric with the planned and actual value for each month, colored green when the actual meets the plan and red when it misses. Red months get a countermeasure from the metric's owner, and repeated reds usually get an A3. The name comes from its resemblance to a bowling score sheet.

Related: Hoshin kanri, X-matrix, Catchball

Break-in work

Break-in work is unplanned maintenance done during a scheduled week that pushes a scheduled job out, such as a breakdown or an urgent repair that cannot wait for the next schedule. Logging each break-in with its hours and the job it displaced shows how much of the week reactive work takes and explains most of the gap in schedule compliance. Jobs pushed out go back to the backlog, usually first in line for the next week's schedule.

Related: Reactive maintenance, Scheduled maintenance, Maintenance backlog, Work order

Breakdown analysis

A breakdown analysis is a written investigation of one equipment breakdown: what was seen, how the machine was restarted, which part failed and why, the countermeasures, and a later check that the failure has not come back. In TPM practice it names which of the five causes of breakdowns was behind it and which standard changed as a result. Sites set their own trigger for one, such as a downtime threshold or any repeat failure.

Related: Zero breakdowns (five countermeasures), Mean time between failures (MTBF), Mean time to repair (MTTR), Root cause analysis (RCA), 5 Whys, Total productive maintenance (TPM)

Calibration

Calibration compares a gauge or instrument with a reference standard of known value, records the difference, and adjusts the gauge if needed so its readings can be trusted. Each gauge is calibrated at a set interval against standards that are themselves traceable to national or international standards, and the readings are recorded as found, before any adjustment, and as left. When a gauge is found out of tolerance, the results it gave since its last good calibration have to be assessed, because parts may have been accepted or rejected wrongly.

Related: Measurement system analysis (MSA), Gauge R&R, Statistical process control (SPC)

Capital expenditure (CapEx)

Capital expenditure (CapEx) is money spent on assets that will be used for more than a year, such as machines, tooling and building changes, as opposed to operating expenses (OpEx) such as wages, materials and repairs, which are charged when they are spent. Capital is depreciated over the asset’s life and comes from a limited yearly budget, so most companies ask for a CapEx request with the options, costs, payback and NPV, approved at a level set by the amount. Where the line between capital and expense falls is set by each company’s accounting policy.

Related: Net present value (NPV), Payback period, Internal rate of return (IRR), Cost-benefit analysis

Catchball

Catchball is the back-and-forth dialogue used in hoshin kanri to agree goals and plans between levels of an organization. A leader proposes an objective, the team below responds with what it would take and what it can commit to, and the plan passes back and forth until both sides agree. The result is targets people understand and own, rather than numbers handed down.

Related: Hoshin kanri, X-matrix, Nemawashi

Causal and resultant losses

A causal loss is the original problem, such as a machine breakdown or a changeover; a resultant loss is a cost it sets off elsewhere, such as operators waiting, overtime or scrap at the restart. Cost deployment in World Class Manufacturing separates the two so resultant costs can be traced back to the causal loss worth fixing. Each loss is counted once, and the causal losses are ranked by their own cost plus the resultant costs they cause.

Related: Cost deployment, World class manufacturing (WCM), Root cause analysis (RCA), Six big losses

Cellular manufacturing

Cellular manufacturing arranges the machines and workstations needed to make a family of similar products close together, often in a U-shape, so parts move from one step to the next with little transport or waiting. A cell is usually run by a small team that can move between stations as demand changes. It is the physical layout that makes one-piece flow practical.

Related: One-piece flow, Chaku-chaku, Just-in-time (JIT)

Chaku-chaku

Chaku-chaku, Japanese for “load-load,” is a way of running a cell in which the machines unload finished parts automatically and the operator’s only job at each station is to load the next part and move on. The operator walks the cell in process order, carrying one part at a time, so the cell runs as one-piece flow with minimal handling. It suits cells where machine cycles are automatic and short.

Related: Cellular manufacturing, One-piece flow

Change point management (4M change)

Change point management is logging every change to the people, machines, materials or methods of a process, the 4M, and checking the product more closely until the change is proven. Typical change points are a relief operator, a repair or new tool, a new material lot or supplier and a revised work instruction; some plants add Design and write 4M1D. Toyota-style plants call a change point henkaten and show current changes by station on a board.

Related: 6Ms of production, First piece inspection, Quality at the source, Engineering change request (ECR)

Check sheet

A check sheet is a simple form for recording how often something happens, and where or when, using tally marks made at the process as events occur. The categories are set in advance, for example defect types by hour or by machine, so the data is collected the same way every time and is ready to analyze. It is often the first of the seven basic quality tools a team uses, and its counts feed Pareto charts and histograms.

Related: Seven basic quality tools, Pareto analysis, Histogram, Stratification, Defects per hundred units

CILR (clean, inspect, lubricate, retighten)

CILR stands for clean, inspect, lubricate, and retighten, the four basic equipment care tasks operators carry out as part of autonomous maintenance. Each machine gets a CILR standard that says which points to check, how, and how often, usually as a short checklist. Regular CILR catches loose fasteners, leaks, contamination, and wear before they turn into breakdowns.

Related: Autonomous maintenance, Total productive maintenance (TPM)

Coaching kata

Coaching kata is a short, fixed routine in which a coach asks a learner five questions about their improvement work: what is the target condition, what is the actual condition now, what obstacles are in the way and which one are you addressing, what is your next step and what do you expect, and when can we go and see what you learned. The learner follows the improvement kata, a repeating pattern of understanding the direction, grasping the current condition, setting the next target condition, and experimenting toward it. Practiced daily, the pair builds scientific problem-solving habits.

Related: PDCA (Plan-Do-Check-Act), Leader standard work, A3 problem solving

Computerized maintenance management system (CMMS)

A computerized maintenance management system (CMMS) is software that keeps a plant’s maintenance records in one place: the asset list, work orders, preventive maintenance schedules, spare parts, and each machine’s repair history. It schedules recurring tasks, tracks each job from request to close, and turns the history into measures such as MTBF and MTTR. An enterprise asset management (EAM) system covers the same ground plus the wider asset life cycle, such as purchasing and replacement planning.

Related: Work order, Preventive maintenance (PM), Planned maintenance, Mean time between failures (MTBF), Mean time to repair (MTTR)

Connected worker platform

A connected worker platform is software that gives frontline workers the instructions, training, issue reporting and checklists they need on shift, on a phone, a tablet or a shared kiosk. It replaces paper binders, whiteboards and spreadsheets at the point of work, and sends what workers record to the people who act on it.

Related: Paperless manufacturing, Digital work instructions, Skills matrix, People, process, technology (PPT)

Containment action

A containment action is the immediate step that stops a problem from reaching the customer or the next process while its root cause is found and fixed. Typical containment includes holding and sorting suspect stock, adding an inspection and posting a quality alert at the line. It protects the customer but does not remove the cause, so it is replaced by a permanent corrective action and then taken away.

Related: 8D problem solving, Non-conformance report (NCR), Corrective and preventive action (CAPA)

Continuous improvement software

Continuous improvement software is a system for managing improvement work from the first idea or reported problem to the measured result. It typically covers capturing ideas and issues from the floor, routing them for review and approval, running improvement projects such as kaizen events, A3s or PDCA cycles, and reporting participation, progress and results. It replaces suggestion boxes, spreadsheets and email trails with one record per improvement.

Related: Kaizen, Kaizen teian, PDCA (Plan-Do-Check-Act), Operational excellence

Corrective and preventive action (CAPA)

CAPA, short for corrective and preventive action, is the quality process for removing the causes of problems. Corrective action eliminates the cause of a nonconformity that has already happened so it does not recur; preventive action removes the cause of a potential problem before it occurs. A CAPA is closed only after its effectiveness has been verified.

Related: Non-conformance report (NCR), 8D problem solving, Root cause analysis (RCA), Supplier corrective action request (SCAR)

Cost deployment

Cost deployment is the World Class Manufacturing method that puts a money value on every loss in a plant, so improvement goes where the cost is highest. Losses are measured by process, split into causal losses and the resultant losses they set off, turned into money with agreed unit costs, and matched with the methods and projects that recover them. The work is usually laid out in matrices labelled A to E, from where losses occur to improvement cost against benefit.

Related: World class manufacturing (WCM), Causal and resultant losses, Six big losses, Cost of poor quality (COPQ), Pareto analysis, Cost-benefit analysis

Cost of poor quality (COPQ)

Cost of poor quality (COPQ) is the cost a business carries because products or processes are not done right the first time. It covers internal failures such as scrap and rework and external failures such as returns, warranty claims, and complaints; broader definitions also count appraisal costs such as inspection. Putting a money value on defects helps rank which quality problems to fix first.

Related: Pareto analysis, Non-conformance report (NCR), Prevention-appraisal-failure (PAF) model

Cost-benefit analysis

A cost-benefit analysis compares what a change will cost with what it will return, over the same years and in the same money terms, to decide whether it is worth doing and which of several options is best. Typical results are the net benefit per year, the payback period, the NPV and the benefit-cost ratio, the present value of the benefits divided by the present value of the costs, where a ratio above 1 means the benefits are larger. Hard benefits, where spending goes down, are usually judged first, with soft benefits shown separately.

Related: Net present value (NPV), Payback period, Hard and soft savings, Capital expenditure (CapEx), Prioritization matrix

Critical to quality (CTQ)

A critical-to-quality (CTQ) characteristic is a measurable property of a product or process that customers care about, with a target and limits, such as a seal strength or an on-time delivery window. Six Sigma teams turn what customers say into CTQs in the Define phase, and a project's primary metric usually measures one of them.

Related: Six Sigma, DMAIC, Project charter, Process capability (Cp, Cpk)

Cross-training

Cross-training is the planned practice of teaching employees to perform jobs beyond their primary role. It gives a plant enough qualified people to cover absences, turnover, and swings in demand without stopping a line or depending on one expert. Progress is usually tracked in a skills matrix so gaps are visible before they cause a problem.

Related: Skills matrix, Job cover matrix

Cycle counting

Cycle counting is counting a small part of the inventory on a regular schedule, so every item is counted over the year and the stock records stay accurate without shutting down for a full physical inventory. Each count is compared with the system quantity, and differences outside tolerance are recounted and traced to their cause, such as an unrecorded issue or a part in the wrong location. Most schedules use an ABC classification so that high-value items are counted most often.

Related: ABC analysis, Inventory record accuracy, Supermarket, Kanban

Cycle time

Cycle time is how long one process step takes to complete one unit, as observed at the station. Comparing each station’s cycle time with takt time shows whether a line can keep up with customer demand and which station is the bottleneck. It is not the same as lead time, which is the total time a unit spends in the process, including waiting.

Related: Takt time, Line balancing, Lead time

Daily huddle

A daily huddle is a short stand-up meeting, usually 10 to 15 minutes at the start of a shift, where a team reviews yesterday's results against target, today's plan and open problems at its board. Problems get an owner and a date instead of being solved in the meeting, and what the team cannot fix is escalated. It is the front-line tier of tiered meetings.

Related: Tiered meetings, Tier board, SQDCM, Leader standard work

Daily kaizen

Daily kaizen is the small, immediate improvement operators or supervisors make in their own area, with no approval process, done the same day or within the shift. Repositioning a tool, fixing a label or adding a hook are typical. Teams make it a habit with a short routine at their board every day, where each fix gets one owner and the fixes are counted every week.

Related: Kaizen, Kaizen teian, Kaizen event, Daily huddle, PDCA (Plan-Do-Check-Act)

Defects per hundred units

Defects per hundred units (DPHU) is the number of defects found per 100 units inspected: total defects divided by units inspected, times 100. Because one unit can carry several defects, it can be higher than the percentage of defective units, which counts each faulty unit once. Tracking both shows whether problems are spread across many parts or concentrated on a few.

Related: Check sheet, First pass yield (FPY), Parts per million (PPM)

Design FMEA (DFMEA)

A design FMEA (DFMEA) is an FMEA of a product design, done by the design team before the design is released, to find how the part could fail to do its job and fix the design while changes are still cheap. Each failure mode is rated for severity, occurrence and detection, where detection is how well design verification and testing would catch it, and the highest risks get actions. It assumes the part is made to the drawing; how the process could fail to make it to the drawing is the job of the process FMEA, which the DFMEA feeds through special characteristics.

Related: Failure mode and effects analysis (FMEA), Poka-yoke, Fault tree analysis (FTA), Production part approval process (PPAP)

Digital work instructions

Digital work instructions are step-by-step job instructions shown on a screen, tablet, or phone at the workstation instead of on paper. They usually combine short text with photos or video, and because they are updated in one place, every station sees the current version. They are how standard work and SOPs reach the operator on the shop floor.

Related: Standard work, Standard operating procedure (SOP)

DMAIC

DMAIC is the five-phase improvement method used in Six Sigma: Define, Measure, Analyze, Improve, and Control. The team defines the problem and goal, measures current performance, analyzes data to confirm root causes, improves the process, and puts controls in place to hold the gain. It suits complex, data-heavy problems where the cause is not obvious.

Related: PDCA (Plan-Do-Check-Act), Root cause analysis (RCA), Six Sigma, SIPOC diagram

Dock-to-stock time

Dock-to-stock time is the time from a delivery being unloaded at the receiving dock to the parts being put away in their location and available to use. It covers checking the delivery against the purchase order, any inspection hold and putaway, so long times usually point to a queue at one of those steps. Material that sits at the dock cannot be used and is easily lost, which is why receiving logs record the putaway time.

Related: Incoming inspection, Lead time, Mizusumashi (water spider), Supermarket

Eight pillars of TPM

The eight pillars of TPM are the areas of work that total productive maintenance is organized into: autonomous maintenance, planned maintenance, quality maintenance, focused improvement, early equipment management, training and education, safety, health and environment, and office TPM. They rest on a foundation of 5S. Each pillar has its own owners and goals, but they depend on each other; autonomous maintenance, for example, relies on the training pillar.

Related: Total productive maintenance (TPM), Autonomous maintenance, Planned maintenance

Employee empowerment

Employee empowerment is giving people the authority, information and resources to make decisions about their own work without asking a manager each time. In practice it means decisions agreed in advance, with clear limits and a named person to consult or escalate to, plus the training to use them. The empowerment guide on this site calls it the opposite of micromanagement.

Related: Employee engagement, Kaizen teian, Daily huddle

Employee engagement

Employee engagement is how committed people are to their work and to the organization's goals, shown in the effort they give beyond the minimum. It is not the same as satisfaction or happiness. The engagement guide on this site names six drivers: recognition, feedback, culture, team, empowerment and development.

Related: Kaizen teian, Leading and lagging indicators

Employee recognition program

An employee recognition program is the set of rules a workplace uses to notice and thank people for specific actions: what is recognized, who can nominate, which rewards are given and who approves them. In a plant it often covers safety reports, improvement ideas, quality catches and helping other teams, and a regular check shows whether recognition reaches every team and shift, not only the people managers see most.

Related: Kaizen teian, Kaizen

Engineering change request (ECR)

An engineering change request (ECR) is the formal request to change a part, drawing, process or document. It says what changes and why, lists everything the change touches, such as tooling, stock on hand, work instructions, the PFMEA and customer approvals, and is reviewed and approved before anything changes on the floor. Once approved, an engineering change notice (ECN) tells everyone affected what changes and when it takes effect; some companies call this step an engineering change order (ECO).

Related: Production part approval process (PPAP), Design FMEA (DFMEA), Failure mode and effects analysis (FMEA), Standard operating procedure (SOP), Digital work instructions

EPEI (every part every interval)

EPEI is how often each product or part number comes round in a production sequence. If a machine makes every part assigned to it at least once every three days, its EPEI is three days. Shorter is better because it means smaller lots and less stock, and it depends mainly on changeover times and the number of parts the machine runs.

Related: Heijunka, Single-minute exchange of die (SMED), Pitch

Equipment criticality analysis

Equipment criticality analysis ranks a plant's assets by the consequences of their failure, usually by scoring safety and environment, quality, production impact, failure frequency, repair time and spare parts lead time. The weighted total sorts assets into classes, often A, B and C, that decide which get condition monitoring and critical spares, which get time-based preventive maintenance and which can run to failure. Criteria, weights and cut-offs are set by each site, and many add a rule that a top safety score makes an asset class A.

Related: Reliability-centered maintenance (RCM), Preventive maintenance (PM), Predictive maintenance (PdM), Reactive maintenance, Failure mode and effects analysis (FMEA), Mean time between failures (MTBF)

Escalation matrix

An escalation matrix is a table that says who is called when a problem cannot be solved where it starts, and when: for each type of issue, who responds first and how fast, and who is called next if the problem is not contained within a set time. It is usually set out by issue type and by tier, from the team leader up to plant leadership. It sits behind andon calls, issue tags and tiered meetings, so each problem reaches someone who can fix it in time.

Related: Tiered meetings, Andon, Daily huddle, Tier board

F-tag

An F-tag is a tag hung on equipment to mark an abnormality found during inspection or daily work, such as a leak, a loose bolt, contamination, or a damaged guard. The F stands for fuguai, Japanese for an abnormality or malfunction. Each tag is logged and stays visible on the machine until the problem is fixed, and tags are often split by whether operators or maintenance should resolve them.

Related: Autonomous maintenance, CILR (clean, inspect, lubricate, retighten), Total productive maintenance (TPM)

Failure mode and effects analysis (FMEA)

Failure mode and effects analysis (FMEA) is a structured way to find how a product or process could fail before it does. For each failure mode the team rates severity, occurrence, and detection, then acts on the highest risks first, traditionally ranked by a risk priority number (RPN) and in newer methods by action priority. Process FMEAs are a standard part of launching and controlling manufacturing processes.

Related: Poka-yoke, Root cause analysis (RCA), Design FMEA (DFMEA)

Fault tree analysis (FTA)

Fault tree analysis (FTA) is a top-down root cause method that starts from one undesired event, such as a machine failure or a safety incident, and works backward through the combinations of events that could cause it. The causes are drawn as a tree joined by AND and OR logic gates, which shows whether one failure alone or several together are needed to produce the top event. It suits complex equipment and safety problems where several causes interact.

Related: Root cause analysis (RCA), Failure mode and effects analysis (FMEA), 5 Whys, Minimal cut set

First pass yield (FPY)

First pass yield (FPY) is the share of units that come through a process step right the first time, with no rework, repair, or scrap. It is calculated as good units made first time ÷ units started × 100. Because reworked units are left out of the good count, FPY exposes the rework that a final yield figure can hide.

Related: Rolled throughput yield (RTY), Right first time (RFT), Cost of poor quality (COPQ)

First piece inspection

A first piece inspection checks the first part made after a setup, a change or a restart against the drawing or the control plan before the run continues. It confirms the process is making good parts now, which is why it follows changeovers, repairs and other change points. It is not the same as a first article inspection, which verifies a new part or a design change once, in full.

Related: Change point management (4M change), Quality at the source, Right first time (RFT)

Fishbone diagram

A fishbone diagram, also called an Ishikawa or cause-and-effect diagram, is a visual tool for brainstorming the possible causes of a problem. The problem sits at the head of the fish and causes are grouped along the bones, often under categories such as man, machine, method, material, measurement, and environment. It organizes ideas for investigation; the likely causes still have to be verified with data.

Related: Root cause analysis (RCA), 5 Whys, 6Ms of production, Seven basic quality tools

Five lean principles

The five lean principles describe how to remove waste from a process: specify value from the customer’s point of view, identify the value stream, make the value-creating steps flow, let the customer pull, and pursue perfection. They were set out by James Womack and Daniel Jones in the book Lean Thinking. The cycle repeats, because each pass exposes more waste to remove.

Related: Lean manufacturing, Value stream mapping (VSM), Pull system

Fixed-position stop

A fixed-position stop is a way of stopping an assembly line at the end of the work cycle, at a set position, when a problem called on the andon cannot be solved within that cycle. The team leader has until the line reaches that position to fix the problem, so many calls can be cleared without stopping the line. It is one way of putting jidoka into practice on a paced line.

Related: Andon, Jidoka, Takt time, Toyota Production System (TPS)

Floor marking

Floor marking is the use of painted or taped lines, colors and symbols on the floor to show aisles, work areas, storage and material locations, and hazards, so anyone can see where things belong and where people and trucks should go. A common scheme uses yellow for aisles and work cells, red for defects and scrap, and striped tape for areas to keep clear, but there is no single universal standard. OSHA requires permanent aisles to be marked and uses red for fire equipment and yellow for physical hazards, and leaves the rest of the scheme to each site, which should write it down and use it the same way in every area.

Related: Visual management, 5S, Shadow board, Red tagging

Gantt chart

A Gantt chart is a project schedule drawn as horizontal bars on a time scale, one bar per task from its start to its finish, with milestones marked as points. Links between tasks show what each one waits for, so a late task shows what it holds up. Improvement teams use one to schedule a project after the charter and to compare planned with actual progress at each review.

Related: Project charter, PDCA (Plan-Do-Check-Act), Kaizen event, RACI matrix

Gauge R&R

Gauge R&R (repeatability and reproducibility) is a study that measures how much of the variation in measurement results comes from the measurement system itself. Repeatability is the variation when one person measures the same part several times with the same gauge; reproducibility is the variation between different people measuring the same parts. The combined result is compared with the part tolerance or the process variation to decide whether the gauge is fit for use.

Related: Measurement system analysis (MSA), Statistical process control (SPC), Process capability (Cp, Cpk)

Gemba

Gemba is a Japanese word meaning “the actual place,” and in lean it means where value is created, most often the shop floor. The principle is that problems are best understood by going there to see the process, the product, and the people directly, rather than relying on reports.

Related: Gemba walk, Genchi genbutsu, 5G methodology

Gemba walk

A gemba walk is a leader’s planned visit to the place where work is done to observe the process, ask questions, and learn from the people doing the work. The aim is to see real conditions and support problem solving, not to inspect people or hand out orders on the spot. What the leader sees is noted and followed up as actions.

Related: Gemba, Layered process audit (LPA), Leader standard work, Genchi genbutsu, Waste walk

Genchi genbutsu

Genchi genbutsu, Japanese for “actual place, actual thing,” is the Toyota principle of going to the source to see a problem for yourself before deciding what to do. Leaders and engineers check the real process, parts, and data at the gemba instead of relying on reports or assumptions. It is the thinking behind gemba walks and the 5G methodology.

Related: Gemba, Gemba walk, 5G methodology

Hansei

Hansei is the Japanese practice of honest self-reflection: looking back at what went wrong or could have gone better, admitting one’s own part in it, and committing to a concrete change. At Toyota it is expected even after a success, on the view that there is always something to improve. Hansei meetings, or hansei-kai, are held at the end of a project or event to capture the lessons before they are lost.

Related: Kaizen, PDCA (Plan-Do-Check-Act), Yokoten, A3 problem solving

Hard and soft savings

Hard savings are reductions in spending that show up in the accounts, such as less material bought, fewer overtime hours paid or a contract cancelled. Soft savings are costs avoided or time and space freed without anyone paying less yet, such as operator hours freed with no change in headcount or overtime. Most CI programs report the two separately and have Finance verify the hard savings before they count toward a target, so the CI team and the plant controller quote the same number.

Related: Cost-benefit analysis, Payback period, Kaizen, Cost of poor quality (COPQ)

Heijunka

Heijunka, or production leveling, is the practice of smoothing the volume and mix of production over a period instead of following the ups and downs of incoming orders. Rather than building all of product A on Monday and all of product B on Tuesday, a leveled schedule makes some of each every day in a repeating sequence. It reduces mura (unevenness), keeps upstream processes and suppliers at a steady pace, and makes just-in-time workable.

Related: Just-in-time (JIT), Muda, mura, muri, Kanban

Histogram

A histogram is a bar chart that shows how many measurements fall into each of a series of equal ranges, so the shape of a process’s variation can be seen at a glance. It shows whether results are centered on the target, how widely they spread, and whether the pattern is skewed or has two peaks, which can mean two machines, shifts, or material lots are mixed together. Drawing the specification limits on it gives a quick visual check of process capability.

Related: Seven basic quality tools, Process capability (Cp, Cpk), Check sheet, Statistical process control (SPC)

Hoshin kanri

Hoshin kanri, also called policy or strategy deployment, is a method for linking a company’s few breakthrough goals to the work of every level of the organization. Goals are cascaded through a back-and-forth negotiation called catchball, often recorded on an X-matrix, and progress is reviewed on a regular PDCA cycle. It keeps improvement effort focused on what matters most to the business.

Related: PDCA (Plan-Do-Check-Act), X-matrix, Catchball, Nemawashi, Bowling chart

Hour-by-hour board

An hour-by-hour board is a visual board at a line or cell that shows planned output against actual output for each hour of the shift, with a short note of the reason whenever an hour falls short. Because it is updated every hour, a missed target becomes a problem the team can act on during the same shift instead of something found in an end-of-day report. The recorded reasons feed the daily meeting and show which losses to attack first.

Related: Visual management, Tier board, Tiered meetings, Andon

Incoming inspection

Incoming inspection, also called receiving inspection, is checking purchased material when it arrives, before it is used or stocked: the paperwork and certificates, the packaging and condition, and a sample checked against the drawing. How many parts to check comes from a sampling plan, often from the ANSI/ASQ Z1.4 or ISO 2859-1 tables with an inspection level and AQL the site chooses. A lot that fails is held and recorded on an NCR, and a SCAR goes to the supplier when the cause is theirs.

Related: Acceptance quality limit (AQL), Supplier corrective action request (SCAR), Non-conformance report (NCR), Supplier scorecard, Dock-to-stock time

Internal rate of return (IRR)

The internal rate of return (IRR) is the discount rate at which a project’s net present value is exactly zero, which makes it the yearly return the project earns on its investment. For a normal project, with the money spent first and the returns after, an IRR above the hurdle rate set by Finance means a positive NPV at that rate. IRR is found by trial or with a spreadsheet function; when comparing options of different sizes, NPV is the safer guide, because a small project can have a high IRR and still add less value.

Related: Net present value (NPV), Payback period, Capital expenditure (CapEx)

Inventory record accuracy

Inventory record accuracy is the share of counted items whose physical count matches the system record within an agreed tolerance: counts within tolerance divided by counts checked, times 100. Tolerances are usually tighter for high-value A items than for C items. Low accuracy shows up as shortages of parts the system says are in stock, extra safety stock, and people keeping their own counts.

Related: Cycle counting, ABC analysis

Is/Is Not analysis

Is/Is Not analysis is a problem definition method that compares what, where, when, and how much a problem occurs with where and when it could occur but does not. The differences between the two columns point to what is distinctive about the problem and rule out causes that cannot explain the pattern. It is used early in 8D and other root cause methods to narrow the search before testing theories.

Related: 5W1H, 8D problem solving, Root cause analysis (RCA)

Jidoka

Jidoka, often translated as autonomation or automation with a human touch, is the lean principle of building quality in by stopping the process as soon as an abnormality occurs. Machines detect problems and stop themselves, and people are empowered to stop the line, so defects are not passed downstream. It is one of the two pillars of the Toyota Production System, alongside just-in-time.

Related: Andon, Poka-yoke, Just-in-time (JIT), Quality at the source, Toyota Production System (TPS)

Jishuken

Jishuken is a hands-on improvement workshop in which a group of managers or engineers studies a real process at the gemba and improves it there, usually over a few days, to build their own kaizen skills. The Japanese term roughly means “self-directed study.” It developed at Toyota, which uses it to train leaders and to support improvement in its own plants and at suppliers, with the lessons spread through yokoten.

Related: Kaizen event, Gemba, Yokoten, Coaching kata

Job breakdown sheet

A job breakdown sheet is the instructor's teaching notes in TWI Job Instruction: a job split into its important steps, the key points within each step, and the reason for each key point. Key points are anything that could make or break the job, injure the worker, or make the work easier. It is kept short so the trainer can read it at a glance while teaching.

Related: TWI Job Instruction, Standard work, One-point lesson (OPL)

Job cover matrix

A job cover matrix is a chart that shows, for each job or station, which people are qualified to cover it and how many backups exist. It exposes single points of failure, such as a machine only one person can run, so supervisors can plan cross-training and staff each shift with confidence. It is closely related to the skills matrix but organized around covering roles.

Related: Skills matrix, Cross-training

Just-in-time (JIT)

Just-in-time (JIT) is a production approach in which each process makes and delivers only what the next process needs, when it needs it, and in the quantity it needs. It relies on pull signals such as kanban, level scheduling, and short changeovers, and it keeps inventory low so problems surface instead of being hidden by stock. JIT and jidoka are the two pillars of the Toyota Production System.

Related: Kanban, Jidoka, Single-minute exchange of die (SMED), Heijunka, Pull system, Toyota Production System (TPS)

Kaikaku

Kaikaku, Japanese for “reform” or “radical change,” is a large, fast step change to a process or system, such as moving a line into cells or redesigning a whole value stream. Where kaizen improves in small, continuous steps, kaikaku is usually led from the top and changes how the work is organized. Plants follow a kaikaku with kaizen to stabilize and refine the new way of working.

Related: Kaizen, Kaizen event, Lean transformation

Kaizen

Kaizen is the practice of continuous improvement through small, frequent changes made by the people who do the work. The Japanese word means “change for the better.” In a plant it shows up as daily problem solving, employee suggestions, and focused improvement events, all aimed at reducing waste and making work easier, safer, and more reliable.

Related: Kaizen event, Kaizen teian, PDCA (Plan-Do-Check-Act), Kaikaku

Kaizen burst

A kaizen burst is the starburst symbol on a value stream map that marks a change needed to reach the future state, such as a shorter changeover or a new supermarket. On its own it is only an idea. In a value stream plan each burst becomes a project with one owner, a target, dates and a way to check that it worked.

Related: Value stream mapping (VSM), Kaizen, Kaizen event, PDCA (Plan-Do-Check-Act)

Kaizen event

A kaizen event, also called a kaizen blitz or rapid improvement event, is a short, focused project, usually lasting a few days to a week, in which a cross-functional team improves one defined process. The team maps the current state, finds the waste, tests changes on the floor, and standardizes the new method before the event closes. Open actions are tracked afterward so the gain holds.

Related: Kaizen, Value stream mapping (VSM), Kaizen newspaper

Kaizen newspaper

A kaizen newspaper is the action list a kaizen team keeps for the items it cannot finish during the event: the problem, the action, who owns it and when it is due, with a status mark updated until each item is closed. It is usually posted in the area and reviewed at the 30, 60 and 90 day follow-ups, so the event's open work stays visible after the team disbands.

Related: Kaizen event, PDCA (Plan-Do-Check-Act)

Kaizen teian

Kaizen teian is a system for collecting and acting on small improvement ideas from individual employees. Most ideas are changes people can make in their own area, and the emphasis is on quick review, recognition, and implementation rather than large savings per idea. It is the individual, everyday side of kaizen, alongside team-based kaizen events.

Related: Kaizen, Kaizen event

Kamishibai board

A kamishibai board is a board of double-sided cards, one per check, used to schedule and track short audits of standard work and process conditions. A card shows green when its check has been done and the process met the standard, and red when the check found a problem or has not been done, so anyone can see audit status at a glance. It is a simple visual way to run leader audits such as layered process audits.

Related: Layered process audit (LPA), Leader standard work, Visual management

Kanban

Kanban is a signal, traditionally a card, that authorizes a process to produce or move a set quantity of parts. When a downstream process uses material, the kanban goes back upstream as the instruction to replace it, so production is pulled by actual use instead of pushed by a forecast. The number of kanban in the loop caps how much inventory can build up.

Related: Just-in-time (JIT), Visual management, Pull system, Supermarket

Layered process audit (LPA)

A layered process audit (LPA) is a short, frequent check that key process steps and controls are being followed, carried out by several layers of the organization, from supervisors up to plant leadership. Each layer audits on a set schedule from a standard question list, and any nonconformance is corrected on the spot or assigned as an action. LPAs are widely used in automotive manufacturing to confirm that high-risk controls stay in place.

Related: Gemba walk, Standard work, Kamishibai board

Lead time

Lead time is the total time from the start of a process to its end as the customer or the next stage experiences it, for example from order to delivery. It includes processing, waiting, inspection, and transport, so it is usually much longer than the time spent actually working on the product. Common types are customer lead time, material lead time, production lead time, and cumulative lead time.

Related: Cycle time, Value-added time, Value stream mapping (VSM), Throughput time, Work in process (WIP)

Leader standard work

Leader standard work is a written routine of the daily, weekly, and monthly tasks a leader performs to sustain the operating system, such as gemba walks, tiered meetings, audits, and checking visual boards. Writing it down makes the leader’s own work visible and repeatable and protects time for coaching and problem solving. It is the management counterpart to operator standard work.

Related: Standard work, Tiered meetings, Gemba walk

Leading and lagging indicators

Lagging indicators measure outcomes after they have happened, such as recordable injuries, lost-time incidents, or customer returns. Leading indicators measure the activities and conditions that come before those outcomes, such as near-miss reports, safety observations, audits completed, or hazards closed. Tracking both lets a plant act on risks before they show up in the results.

Related: Near miss, Behavior-based safety (BBS), SQDCM

Lean manufacturing

Lean manufacturing is a way of running production that aims to deliver what the customer values with the least waste of time, material, effort, and money. It grew out of the Toyota Production System and combines principles such as flow, pull, and continuous improvement with tools such as 5S, standard work, and value stream mapping. In practice it depends as much on how people solve problems every day as on the tools.

Related: Five lean principles, Toyota Production System (TPS), 8 wastes of lean (DOWNTIME)

Lean readiness assessment

A lean readiness assessment checks, before a lean rollout, whether the organization has the foundation lean depends on: leadership commitment, a culture that surfaces problems, processes stable enough to standardize, and people with the time and experience to take part. Several people score the same statements on their own, and the weakest factor and the gaps between their views show what to fix first and where to pilot. Repeated later, it shows whether the gaps have closed.

Related: Lean transformation, Lean manufacturing, Five lean principles

Lean transformation

A lean transformation is an organization-wide change to working by lean principles, covering how work flows, how problems are surfaced and solved, and how leaders manage, rather than applying a few tools in one area. It usually starts in a pilot area or value stream and spreads as people and systems are ready. Because it changes daily habits and management routines, it is treated as an ongoing change, not a project with an end date.

Related: Lean manufacturing, Hoshin kanri, Leader standard work

Line balancing

Line balancing is the practice of distributing work across the stations of a line so that each station’s workload is close to takt time and to the others. A balanced line has less waiting and fewer bottlenecks, and it needs fewer operators to meet the same demand. Yamazumi charts are the usual tool for seeing and redistributing the work.

Related: Takt time, Cycle time, Yamazumi chart, Theory of constraints (TOC), Bottleneck

Little’s Law

Little’s Law says that in a stable process the average time a unit spends in the process equals the average number of units in it divided by the rate at which they leave: lead time = WIP ÷ throughput. 1,600 parts waiting in front of a step that uses 400 a day means about 4 days of waiting. It is how value stream maps turn counted inventory into days.

Related: Throughput time, Work in process (WIP), Lead time, Throughput

Lockout/tagout (LOTO)

Lockout/tagout (LOTO) is the safety procedure that isolates a machine from all hazardous energy sources and keeps it isolated while people service or maintain it. Each authorized worker applies their own lock and tag to the energy-isolating devices, and the absence of energy is verified before work begins. In the United States, the requirements are set by OSHA standard 29 CFR 1910.147.

Related: Standard maintenance procedure (SMP), Behavior-based safety (BBS)

Maintenance backlog

Maintenance backlog is the approved maintenance work that has not been done yet, usually counted in weeks: estimated hours of backlog ÷ crew hours available per week. 360 hours of backlog with 120 crew hours a week is 3 weeks. A backlog that keeps growing means work arrives faster than the crew can do it; one near zero can mean work is not being planned ahead.

Related: Work order, Computerized maintenance management system (CMMS), PM compliance, Planned maintenance percentage (PMP)

Mean time between failures (MTBF)

Mean time between failures (MTBF) is the average time a repairable machine runs between breakdowns. It is calculated as total operating time ÷ number of failures in that period, so a machine that ran 1,000 hours with 5 failures has an MTBF of 200 hours. A rising MTBF shows equipment is becoming more reliable; it is usually tracked alongside mean time to repair (MTTR), the average time to restore a machine after a failure.

Related: Mean time to repair (MTTR), Preventive maintenance (PM), Reliability-centered maintenance (RCM), Unplanned downtime

Mean time to repair (MTTR)

Mean time to repair (MTTR) is the average time it takes to restore a failed machine to working order. It is calculated as total repair time ÷ number of repairs in that period, so 20 hours spent on 5 repairs gives an MTTR of 4 hours. Plants differ on whether repair time covers the whole outage, including diagnosis and waiting for parts, or only hands-on work, so the definition should be stated with the number; a falling MTTR means breakdowns are being fixed faster.

Related: Mean time between failures (MTBF), Unplanned downtime, Work order, Computerized maintenance management system (CMMS)

Measurement system analysis (MSA)

Measurement system analysis (MSA) is a set of studies that checks whether a measurement system, meaning the gauge, the method, the people, and the conditions, gives data good enough to base decisions on. It looks at bias, linearity, stability, repeatability, and reproducibility, with gauge R&R the most common study. If the measurement system is not adequate, control charts, capability studies, and pass/fail decisions built on its data cannot be trusted.

Related: Gauge R&R, Process capability (Cp, Cpk), Statistical process control (SPC)

Micro-stops

Micro-stops are brief stoppages, from a few seconds to a few minutes, that interrupt a machine or line without being logged as downtime, such as jams, misfeeds, or sensor trips an operator clears by hand. Because each one is short they are rarely recorded, yet together they can be a large hidden loss. In OEE they count as a performance loss and are one of the six big losses.

Related: Overall equipment effectiveness (OEE), Six big losses

Milk run

A milk run is a fixed route run at fixed times that delivers or collects material at several stops in one loop, instead of a separate trip for each. Inside a plant it feeds lines from a supermarket, often run by a water spider; outside, a truck collects small loads from several suppliers. Fixed timing lets each stop plan around the next visit and keeps the stock between visits small.

Related: Mizusumashi (water spider), Supermarket, Kanban, Pull system

Minimal cut set

A minimal cut set is the smallest combination of basic events in a fault tree that together cause the top event: take away any one of them and that combination no longer causes it. A cut set with a single event is a single point of failure, and a cut set with two or more events shows where independent safeguards protect the system. With independent events, the probability of a cut set is the product of its events' probabilities.

Related: Fault tree analysis (FTA), Failure mode and effects analysis (FMEA), Root cause analysis (RCA)

Mizusumashi (water spider)

A mizusumashi, or water spider, is a material handler who runs a fixed, timed route delivering parts to production lines and collecting empty containers and kanban. By keeping materials at the point of use, the role lets operators stay at their stations doing value-added work. Because the route and timing are standardized, the water spider also carries the pull signals between supermarkets and the line.

Related: Supermarket, Kanban, Pull system, Milk run

Model line

A model line is one production line or area where a plant first puts lean practices in place and proves they work before spreading them to other areas. The team builds the foundations there, such as 5S, standard work, visual management and a daily team meeting, then flow and pull, and writes what works into standards the next areas start from. Concentrating the effort on one line builds people's skill and gives the rest of the plant a working example to copy.

Related: Lean transformation, Standard work, 5S, Kaikaku

Muda, mura, muri

Muda, mura, and muri are the three types of waste in the Toyota Production System. Muda is any activity that adds no value for the customer, mura is unevenness in workload or flow, and muri is overburden on people or equipment. They are linked: uneven schedules (mura) push people and machines past their limits (muri), which creates waste (muda).

Related: 8 wastes of lean (DOWNTIME)

Near miss

A near miss is an unplanned event that could have caused injury, illness, or damage but did not, often by luck or a last-second reaction. Reporting and investigating near misses lets a plant fix hazards before someone gets hurt. A strong reporting culture depends on reports being easy to make, free of blame, and visibly acted on.

Related: Behavior-based safety (BBS), Root cause analysis (RCA)

Nemawashi

Nemawashi is the practice of building consensus for a proposal informally, one to one with each person affected, before it goes to a formal decision. The word comes from Japanese gardening, where it means preparing the roots before moving a tree. It surfaces concerns early, improves the proposal, and makes the decision faster and easier to carry out.

Related: Catchball, Hoshin kanri, A3 problem solving

Net present value (NPV)

Net present value (NPV) is the value today of a project’s future cash flows minus the investment. Each year’s net cash flow is divided by (1 + r) raised to the number of years from now, where r is the discount rate set by Finance, the results are added up, and the investment is subtracted. A positive NPV means the project returns more than the rate Finance requires; unlike simple payback, NPV counts every year of the project and the time value of money.

Related: Payback period, Internal rate of return (IRR), Capital expenditure (CapEx), Cost-benefit analysis

Non-conformance report (NCR)

A non-conformance report (NCR) is a record that a product, material, or process did not meet a specified requirement. It documents what was found, where, and how much is affected, along with the decision on what to do with it, such as rework, scrap, use as is, or return to the supplier. Serious or recurring nonconformances are escalated to a CAPA to find and remove the root cause.

Related: Corrective and preventive action (CAPA), Cost of poor quality (COPQ), Supplier corrective action request (SCAR), Incoming inspection

Obeya

An obeya, Japanese for “big room,” is a dedicated room where a cross-functional team keeps all the key information for a project or strategy on the walls, such as goals, schedules, metrics, problems, and countermeasures. The team meets there regularly, standing at the visuals to review status and make decisions quickly. It began at Toyota in product development and is now also used to manage plant performance and strategy.

Related: Visual management, Hoshin kanri, Tiered meetings

On-time delivery (OTD)

On-time delivery (OTD) is the share of deliveries that arrive within the agreed window: on-time deliveries divided by all deliveries, times 100. The window has to be agreed first, for example up to two days early and none late, and some companies count order lines instead of deliveries. It is used to rate suppliers and as a plant’s own delivery measure to its customers; on-time in full (OTIF) also requires the full quantity.

Related: Supplier scorecard, SQDCM, Leading and lagging indicators

One-piece flow

One-piece flow means moving products through a process one unit at a time, with each step making only what the next step needs and passing it on immediately, instead of in batches. It cuts work-in-process and lead time and exposes defects quickly, because a problem is found at the next step instead of after a whole batch is made. It usually needs a cell layout, balanced work, and reliable equipment.

Related: Cellular manufacturing, Just-in-time (JIT), Chaku-chaku

One-point lesson (OPL)

A one-point lesson (OPL) is a single-page visual training sheet that teaches one piece of knowledge or one skill, such as how to read a gauge or set a guide. It is mostly pictures with little text, can be read in a few minutes at the machine, and is often written by operators or technicians themselves. OPLs are widely used in TPM and autonomous maintenance to share know-how quickly.

Related: Autonomous maintenance, Standard work, TWI Job Instruction

Operational excellence

Operational excellence is the ability of an organization to deliver consistently on safety, quality, delivery, and cost while steadily improving, because good performance is built into how daily work is run. In manufacturing it combines lean, quality, and maintenance methods with standard work, daily management, and leadership routines that keep them going. It describes a way of operating rather than a single program or tool.

Related: Lean manufacturing, World class manufacturing (WCM), Tiered meetings

Overall equipment effectiveness (OEE)

Overall equipment effectiveness (OEE) measures how much of a machine’s planned production time is truly productive. It is calculated as availability × performance × quality: the share of planned time the machine runs, how fast it runs against its ideal rate, and the share of parts that are good. A score of 100% means only good parts, made as fast as possible, with no stop time.

Related: Six big losses, Micro-stops, Total productive maintenance (TPM), Unplanned downtime, Total effective equipment performance (TEEP)

Pacemaker process

The pacemaker process is the one process in a value stream that receives the customer schedule. Processes upstream of it are replenished by pull from supermarkets, and material downstream of it moves in continuous flow or a FIFO lane, so its pace sets the pace of the whole stream. It is usually the last step of continuous flow before the customer, and the place where the product mix is leveled.

Related: Value stream mapping (VSM), Heijunka, Supermarket, Pull system, Takt time

Paperless manufacturing

Paperless manufacturing is running and reporting the daily work of a plant without paper forms, checklists and documents: checks, logs, audits and instructions are filled in and read on phones, tablets or screens. The data is entered once where the work happens, so the people who act on it do not wait for paper to be collected, typed up or filed. A common way to start is form by form, beginning with the forms that take the most time or wait longest before anyone reads them.

Related: Digital work instructions, 8 wastes of lean (DOWNTIME), Value-added time, Standard work

Pareto analysis

Pareto analysis ranks problems or causes by their impact, usually as a bar chart sorted from largest to smallest with a cumulative percentage line. It rests on the 80/20 rule of thumb that a few causes account for most of the effect. Teams use it to decide which defects, downtime reasons, or losses to work on first.

Related: Root cause analysis (RCA), Cost of poor quality (COPQ), Check sheet, Seven basic quality tools

Parts per million (PPM)

In quality, parts per million (PPM) is the number of defective parts for every million made, shipped or received: defective parts divided by total parts, times 1,000,000. Eight rejects in 10,000 parts received is 800 PPM. It is the usual way to state supplier and customer quality, because percentages become hard to read once defect rates are small.

Related: Supplier scorecard, First pass yield (FPY), Six Sigma

Payback period

The payback period is how long a project takes to earn back its investment: the investment divided by the annual net benefit, which is the yearly saving or extra income minus any yearly running costs. A $120,000 machine that returns $40,000 a year net pays back in 3 years. It is quick to work out and easy to explain, but it ignores the time value of money and everything after the payback date, which is why capital requests usually show NPV as well.

Related: Net present value (NPV), Internal rate of return (IRR), Capital expenditure (CapEx), Cost-benefit analysis, Hard and soft savings

PDCA (Plan-Do-Check-Act)

PDCA, short for Plan-Do-Check-Act, is the four-step cycle behind continuous improvement. You plan a change based on what you expect it to do, try it on a small scale, check the results against the expectation, and act by standardizing what worked or starting another cycle. It is also known as the Deming or Shewhart cycle, and some practitioners use PDSA, with Study in place of Check.

Related: DMAIC, A3 problem solving, Kaizen

People, process, technology (PPT)

People, process, technology (PPT) is a framework for planning and checking a change by looking at three elements together: the people who do the work, the processes that set how it is done and the technology that supports them. The point is balance: a new tool adds little if the people are not trained or the process was not changed to fit it, so the weakest element limits the result. It is also called the golden triangle.

Related: Lean readiness assessment, Paperless manufacturing, Digital work instructions, Nemawashi

Pitch

Pitch is the time a process needs to make one container of product: takt time × pack-out quantity. With a takt time of 120 seconds and 15 pieces to a container, the pitch is 30 minutes. Pitch sets the interval for releasing and collecting work, for example how often a kanban is taken from a heijunka box.

Related: Takt time, Heijunka, Kanban, EPEI (every part every interval)

Planned downtime

Planned downtime is time a machine or line is deliberately stopped on a schedule, for example for planned maintenance, changeovers, cleaning, trials, or breaks. Because it is known in advance, parts, people, and the production plan can be prepared for it. Plants set their own rules for which planned stops count against OEE, so the rule should be written down and applied consistently.

Related: Unplanned downtime, Planned maintenance, Overall equipment effectiveness (OEE)

Planned maintenance

Planned maintenance is maintenance work that is prepared in advance: the job is defined, and the steps, parts, tools, skills, and time it needs are worked out before it starts. It covers preventive and predictive tasks as well as repairs that can be prepared ahead of time. In TPM, planned maintenance is also the pillar through which the maintenance team builds a proactive program.

Related: Scheduled maintenance, Preventive maintenance (PM), Eight pillars of TPM

Planned maintenance percentage (PMP)

Planned maintenance percentage (PMP) is the share of maintenance hours spent on work that was planned before it was done: planned hours ÷ total maintenance hours. Planned work includes preventive and predictive tasks, inspections and repairs scheduled ahead; the rest is reactive work after a breakdown. Plants draw the line between the two differently, so the definition should be written down next to the number.

Related: Planned maintenance, Reactive maintenance, PM compliance, Maintenance backlog

PM compliance

PM compliance is the share of preventive maintenance tasks due in a period that were done on time: PMs done on time ÷ PMs due. Many plants count a PM as on time if it is done inside a grace window they set, such as 10% of the interval, and count late PMs as done but not on time. A falling PM compliance is often the first sign that breakdown work is crowding out planned work.

Related: Preventive maintenance (PM), Planned maintenance percentage (PMP), Mean time between failures (MTBF), Maintenance backlog

Points-based reward system

A points-based reward system gives employees a set number of points for each action it recognizes and lets them save the points and redeem them for rewards they choose from a catalogue. The workplace sets the points per action and per prize, so the rules are visible and small, frequent recognition adds up. Points earned and not yet redeemed are a future cost to budget for.

Related: Kaizen teian

Poka-yoke

Poka-yoke, Japanese for mistake-proofing, is any device or method that prevents an error from being made, or makes it obvious at once so it cannot become a defect. Examples include fixtures that only accept a part the right way round, sensors that stop a machine when a step is skipped, and connectors that cannot be mated incorrectly. It builds quality in at the source instead of relying on inspection.

Related: Jidoka, Failure mode and effects analysis (FMEA), Poka-yoke types, Quality at the source

Poka-yoke types

Poka-yoke devices are commonly grouped into three types by how they catch an error. Contact methods check a physical feature of the part, such as its shape, size, or position; fixed-value methods check that the right number of parts or actions has been completed; and motion-step methods check that the steps of a process were done in the right order. Each type can either prevent the error or warn when it happens.

Related: Poka-yoke, Quality at the source, Jidoka

Pre-shipment inspection

A pre-shipment inspection is the last check of an order before it leaves the building: the right part and revision, the right quantity, released lots, labels in the customer’s format, packaging as specified, complete paperwork and photos, followed by a release by an authorized person. Final inspection checks that the product meets its specification; pre-shipment inspection checks that the right product is packed, labeled and documented correctly. It catches the complaints that are not about the part itself, such as wrong quantities, mixed lots and missing certificates.

Related: Acceptance quality limit (AQL), Quality at the source, Poka-yoke, Check sheet

Predictive maintenance (PdM)

Predictive maintenance (PdM) schedules maintenance based on the measured condition of the equipment rather than on the calendar. Readings such as vibration, temperature, oil analysis, or current draw are monitored for signs of deterioration, and the repair is planned before failure is expected. It avoids both unexpected breakdowns and replacing parts that still have useful life.

Related: Preventive maintenance (PM), Reliability-centered maintenance (RCM), Mean time between failures (MTBF)

Prevention-appraisal-failure (PAF) model

The prevention-appraisal-failure (PAF) model sorts the cost of quality into four categories: prevention costs such as training and error-proofing, appraisal costs such as inspection and testing, internal failure costs such as scrap and rework, and external failure costs such as returns and warranty claims. The two failure categories make up the cost of poor quality. Spending more on prevention usually reduces the other three.

Related: Cost of poor quality (COPQ), First pass yield (FPY)

Preventive maintenance (PM)

Preventive maintenance (PM) is maintenance done at set intervals of time or usage, such as monthly or every set number of running hours, to keep equipment from failing. Typical tasks are inspections, lubrication, adjustments, and replacing wear parts before they fail. It reduces breakdowns but can replace parts earlier than needed, which is why it is often combined with predictive maintenance.

Related: Predictive maintenance (PdM), Planned maintenance, Reactive maintenance, Computerized maintenance management system (CMMS)

Prioritization matrix

A prioritization matrix is a grid for ranking improvement ideas or problems, most often by impact on one axis and effort on the other. High-impact, low-effort items are done first, high-impact, high-effort items are planned as projects, and low-impact items are simplified or dropped. It turns a long backlog into an agreed order of work.

Related: Pareto analysis, Kaizen

Process capability (Cp, Cpk)

Process capability measures how well a stable process can produce output within its specification limits. Cp compares the width of the tolerance with the spread of the process, (USL − LSL) ÷ 6σ, while Cpk also accounts for centering and is the smaller of (USL − mean) ÷ 3σ and (mean − LSL) ÷ 3σ. A Cpk of 1.33 is a commonly used minimum (a rule of thumb, not a universal standard), and the result is only meaningful when the process is in statistical control.

Related: Statistical process control (SPC), Measurement system analysis (MSA), Six Sigma, Process performance (Pp, Ppk)

Process capacity sheet

A process capacity sheet lists each machine in a process with its manual time, automatic time and tool change time, and works out how many pieces it can make in a shift: available time divided by the time per piece, including each piece's share of the tool changes. It shows which machine limits capacity before the operator's work is designed around it with a combination table.

Related: Standard work combination table, Cycle time, Takt time

Process cycle efficiency (PCE)

Process cycle efficiency (PCE) is the share of a process's lead time spent on value-added work: value-added time ÷ lead time, in the same units. A part with 110 seconds of value-added work and a 17-day lead time has a PCE of about 0.01%. Very low figures are normal in batch production; they show that almost all of the lead time is waiting, which is where improvement should start.

Related: Value-added time, Lead time, Value stream mapping (VSM), Little’s Law

Process flow diagram

A process flow diagram is a drawing of every step a product goes through, in order, from the material coming in to the product going out, using symbols for operations, moves, inspections, delays and storage, with the decisions and rework loops between them. Counting the steps of each kind shows how few of them change the part, and the process FMEA and control plan follow the same steps; in automotive PPAP it is a required element. Unlike a value stream map, it does not show cycle times, inventory between steps or information flow.

Related: Value stream mapping (VSM), Spaghetti diagram, SIPOC diagram, Value-added time, Production part approval process (PPAP)

Process improvement

Process improvement, also called business process improvement (BPI), is the ongoing work of finding, analyzing and improving existing processes so they take less time and go wrong less often. Common methodologies include lean, kaizen, PDCA, 5 Whys, total quality management and Six Sigma, and the one that fits depends on the problem: its size, its cause and the data available.

Related: Kaizen, PDCA (Plan-Do-Check-Act), Six Sigma, Lean manufacturing, Total quality management (TQM), 5 Whys

Process performance (Pp, Ppk)

Pp and Ppk are process performance indices: they use the same formulas as Cp and Cpk, but with the overall standard deviation of every reading, which includes shifts and drift between subgroups, instead of the short-term variation within subgroups. Pp = (USL − LSL) ÷ 6σ, and Ppk is the smaller of (USL − mean) and (mean − LSL), divided by 3σ. When a process is stable Ppk and Cpk are close; a Ppk well below Cpk means the process moves over time, and PPAP initial process studies usually report Ppk.

Related: Process capability (Cp, Cpk), Statistical process control (SPC), Production part approval process (PPAP)

Production part approval process (PPAP)

The production part approval process (PPAP) is how a supplier, mainly in automotive, shows its customer that it understands every requirement for a part and that its production process can make the part to those requirements at the quoted rate. The AIAG PPAP manual lists 18 elements, from the design records, process flow diagram and FMEAs to capability studies and the part submission warrant (PSW), and five submission levels that set what is sent to the customer and what is kept on file. A new submission is usually needed for a new part and for changes such as new tooling, a new material or a move to another site.

Related: Design FMEA (DFMEA), Process flow diagram, Process performance (Pp, Ppk), Measurement system analysis (MSA), Engineering change request (ECR)

Project charter

A project charter is the one-page agreement that starts an improvement project, signed by the sponsor before the analysis begins. It states the business case, the problem in numbers, the goal with a date, the metrics, the scope, the team and the phase milestones. In DMAIC it is the main output of the Define phase and is updated at a tollgate if the data changes the picture.

Related: DMAIC, SIPOC diagram, Critical to quality (CTQ), Six Sigma

Pull system

A pull system is a way of controlling production in which a process makes or moves material only when the next process signals that it has used some, instead of following a forecast-driven schedule (push). The signal can be a kanban card, an empty container or space, or an electronic trigger. Because work is released only as it is consumed, inventory stays capped and overproduction is avoided.

Related: Kanban, Supermarket, Just-in-time (JIT)

Pulse survey

A pulse survey is a short survey, often a dozen or so statements, run at regular intervals to see how people view their work between longer surveys. Because it is short and repeated with the same statements, results can be compared over time and actions checked against the next round.

QA matrix

A QA matrix (quality assurance matrix) is a table of defect modes against the process stations in flow order that marks where each defect is made and where it is first caught. It shows which stations make defects, which checks catch them, how far a defect travels before it is found and which defects reach the customer, and ratings rank the defects so the most important are fixed first. It is common in TPM and World Class Manufacturing quality work, and each plant sets its own format and scales.

Related: Prioritization matrix, Failure mode and effects analysis (FMEA), Quality at the source, World class manufacturing (WCM), Poka-yoke

Quality alert

A quality alert is a notice posted at the line after a defect is found, showing what the defect looks like next to a good part, how to check for it and what to do if it is found. Every operator on every shift is briefed and signs it, and it stays up until its review date or until the cause is fixed. It is a containment step, not a fix: the cause is dealt with through an NCR or a CAPA.

Related: Non-conformance report (NCR), Corrective and preventive action (CAPA), Quality at the source, Jidoka

Quality at the source

Quality at the source means each person and process makes sure their own output is right before passing it on, instead of relying on inspection at the end. Operators are given the standards, gauges, and error-proofing to check their own work, and they can stop the process when something is wrong. It is the principle behind jidoka and poka-yoke.

Related: Jidoka, Poka-yoke, Right first time (RFT)

Quality circle

A quality circle is a small group of employees from the same work area, usually with their supervisor, who meet regularly to find, analyze, and solve problems in their own work. Members are trained in simple problem-solving tools such as Pareto charts, fishbone diagrams, and check sheets, and they carry out fixes within their area of authority. The practice is associated with Kaoru Ishikawa and spread widely through Japanese industry.

Related: Kaizen, Pareto analysis, Fishbone diagram

RACI matrix

A RACI matrix is a table that lists the tasks or decisions in a process against the people or roles involved and marks each as responsible (does the work), accountable (owns the outcome and signs off), consulted (gives input beforehand), or informed (kept up to date). Each task should have exactly one accountable person. It removes confusion about who does what, especially in cross-functional projects and handoffs.

Related: Kaizen event, A3 problem solving

Reactive maintenance

Reactive maintenance means repairing equipment only after it has broken down, also called run-to-failure or breakdown maintenance. It can be a sensible choice for cheap, non-critical items, but as the main strategy it leads to unplanned downtime, rushed repairs, and higher costs. Proactive approaches, such as preventive, predictive, and autonomous maintenance, aim to catch problems before failure.

Related: Preventive maintenance (PM), Unplanned downtime, Reliability-centered maintenance (RCM)

Red tagging

Red tagging is the standard technique for the Sort step of 5S. Any item whose need in the area is in doubt gets a red tag and is moved to a holding area, where it stays for a set period before being returned, relocated, or disposed of. It clears out unneeded tools, materials, and equipment without people having to decide everything on the spot.

Related: 5S, 5S audit, Shadow board

Reliability-centered maintenance (RCM)

Reliability-centered maintenance (RCM) is a structured method for choosing the right maintenance approach for each asset based on its functions, how it can fail, and the consequences of each failure. For every failure mode the team picks a task, such as condition monitoring, scheduled replacement, a redesign, or deliberately running to failure, that is technically feasible and worth doing. It focuses maintenance effort on the failures that matter most for safety, production, and cost.

Related: Preventive maintenance (PM), Predictive maintenance (PdM), Failure mode and effects analysis (FMEA)

Right first time (RFT)

Right first time (RFT) is the goal, and the measure, of doing every task correctly the first time, with no rework, repair, correction, or repeat. As a metric it is the share of units, batches, or documents that pass without any correction, much like first pass yield. It is achieved by building quality into the process through capable processes, clear standards, and error-proofing rather than by inspection.

Related: First pass yield (FPY), Quality at the source, Process capability (Cp, Cpk)

Rolled throughput yield (RTY)

Rolled throughput yield (RTY) is the probability that a unit passes through every step of a multi-step process without any rework or scrap. It is calculated by multiplying the first pass yields of the steps, so three steps at 95% FPY each give an RTY of about 86%. Because losses compound, RTY shows the end-to-end quality of a line better than any single step’s yield.

Related: First pass yield (FPY), Six Sigma, Cost of poor quality (COPQ)

Root cause analysis (RCA)

Root cause analysis (RCA) is the process of finding the underlying reason a problem occurred, so the fix prevents it from happening again instead of treating the symptom. Common tools include the 5 Whys, fishbone diagrams, Pareto analysis, and fault tree analysis. A root cause is confirmed when removing it stops the problem from coming back.

Related: 5 Whys, Fishbone diagram, 8D problem solving, Corrective and preventive action (CAPA)

Safety cross

A safety cross is a calendar in the shape of a cross, with one square for each day of the month, that a team colours each day by the most serious safety event of that day. The colours are set by the site, for example green for no incident and red for an injury, and the cross is reviewed at the daily huddle so the month's record and any pattern show at a glance. A green day only means nothing was reported, so it is read together with the near miss count.

Related: Near miss, Daily huddle, Visual management, Leading and lagging indicators

Sangen shugi (three actuals)

Sangen shugi, Japanese for the “three actuals” principle, is the habit of checking the actual place (genba), the actual thing (genbutsu) and the actual facts (genjitsu) before deciding anything about a problem. It is genchi genbutsu written as a checklist. The 5G methodology adds two more: the principles that govern the process (genri) and the standard it should follow (gensoku).

Related: 5G methodology, Genchi genbutsu, Gemba

Scatter diagram

A scatter diagram plots pairs of measurements as points on two axes to show whether one variable changes with another, for example oven temperature against the number of defects. Points that cluster along a line or curve suggest a relationship, while a shapeless cloud suggests none. A pattern shows correlation, not cause, so a suspected cause still has to be confirmed with a test or at the gemba.

Related: Seven basic quality tools, Root cause analysis (RCA), Histogram

Schedule compliance (maintenance)

Maintenance schedule compliance is the share of the jobs on the week's schedule that were done as scheduled: jobs done as scheduled ÷ jobs scheduled, or the same with the jobs' estimated hours. 14 of 16 scheduled jobs is 87.5%. It is not the same as PM compliance, which counts only preventive tasks against their due dates, and sites differ on whether a job counts if it was done in its week or only on its day.

Related: Scheduled maintenance, PM compliance, Planned maintenance, Maintenance backlog

Scheduled maintenance

Scheduled maintenance decides when planned maintenance work will be done and who will do it, fitting jobs into production windows and technician availability. Planning answers what and how; scheduling answers when and by whom. The two terms are often used interchangeably, but they are separate steps, and a job should be planned before it is scheduled.

Related: Planned maintenance, Planned downtime, Preventive maintenance (PM)

Scrum

Scrum is a framework in which a small team works in sprints of one month or less, each with one sprint goal, and holds four timed events in every sprint: sprint planning, the daily scrum, the sprint review and the sprint retrospective. The roles are the Product Owner, the Scrum Master and the people doing the work, called developers. It is set out in the Scrum Guide by Ken Schwaber and Jeff Sutherland, last revised in 2020.

Related: Daily huddle, PDCA (Plan-Do-Check-Act), Hansei, Visual management

Seven basic quality tools

The seven basic quality tools are a set of simple charts and methods for collecting and analyzing quality data: the check sheet, Pareto chart, cause-and-effect (fishbone) diagram, histogram, scatter diagram, control chart, and stratification. Kaoru Ishikawa promoted them in Japan so that front-line teams, not only specialists, could solve most everyday quality problems themselves. Some lists replace stratification with a flowchart.

Related: Check sheet, Pareto analysis, Fishbone diagram, Histogram, Scatter diagram, Statistical process control (SPC), Stratification, Quality circle

Shadow board

A shadow board is a board with the outline of each tool drawn or cut out where it hangs, so every tool has a fixed home and a missing one is noticed at once. It is a common Set in order tool in 5S and a simple example of visual management. Boards are kept at the point of use, and the outlines are often labeled with the tool name or size.

Related: 5S, Visual management, Red tagging, Floor marking

Single-minute exchange of die (SMED)

Single-minute exchange of die (SMED) is a method for cutting changeover time, the time from the last good part of one product to the first good part of the next. Its core idea is to separate internal work, which can only be done with the machine stopped, from external work that can be done while it runs, then move as much as possible to external and streamline both. The name reflects the goal of changeovers under ten minutes, a single-digit number of minutes.

Related: Just-in-time (JIT), Overall equipment effectiveness (OEE)

SIPOC diagram

A SIPOC diagram is a one-page, high-level map of a process that lists its suppliers, inputs, process steps, outputs, and customers in five columns. The process column is kept to a handful of main steps, so the team agrees on where the process starts and ends, and who it serves, before mapping it in detail. It is commonly used in the Define phase of DMAIC and at the start of improvement projects.

Related: DMAIC, Value stream mapping (VSM), Six Sigma

Six big losses

The six big losses are the main causes of lost productivity on equipment, grouped under the three OEE factors: equipment failures and setup and adjustments (availability), idling and minor stops and reduced speed (performance), and process defects and reduced yield at startup (quality). Naming losses this way tells a team where OEE is being lost and what kind of fix is needed.

Related: Overall equipment effectiveness (OEE), Micro-stops, Total productive maintenance (TPM)

Six Sigma

Six Sigma is a data-driven method for reducing variation and defects in a process, organized around the DMAIC cycle and statistical tools. The name refers to a process so well controlled that it produces no more than 3.4 defects per million opportunities. Lean Six Sigma combines it with lean’s focus on flow and waste, and practitioners are trained in levels called belts, such as Green Belt and Black Belt.

Related: DMAIC, Statistical process control (SPC), Process capability (Cp, Cpk)

Skills matrix

A skills matrix, also called a competency or training matrix, is a grid that shows each employee’s level of proficiency in each skill or task their area needs. It shows at a glance who is trained, who is in training, and where the team is thin, so leaders can plan training and cross-training. Most matrices use a simple scale, for example from not trained to able to train others.

Related: Cross-training, Job cover matrix

SMART goals

SMART goals are goals written to pass five tests: Specific, Measurable, Achievable, Relevant and Time-bound. In a plant that means one metric with a baseline and a target, a named line or area and an owner, a link to a plant objective and a deadline, for example cutting scrap on Line 3 from 5.0% to 3.0% of parts made by 31 December. Progress is then reviewed against the target on dates set in advance.

Related: Hoshin kanri, Catchball, Bowling chart, Leading and lagging indicators

Spaghetti diagram

A spaghetti diagram is a drawing of the actual path a person, product, or document takes through a work area, traced as one continuous line on a floor layout. The tangle of lines makes wasted walking, transport, backtracking, and crossing flows visible, and the total distance can be measured. Teams draw one at the gemba before and after a layout change to show what it saved.

Related: 8 wastes of lean (DOWNTIME), Waste walk, Cellular manufacturing, Value stream mapping (VSM)

SQDCM

SQDCM stands for safety, quality, delivery, cost, and morale, the five categories many plants use to organize daily performance boards and tiered meetings. Each category has a few simple measures that are reviewed every shift or day against target, and misses are turned into actions. Some sites use SQDC without morale, or swap in people or environment.

Related: Tiered meetings, Visual management

Standard maintenance procedure (SMP)

A standard maintenance procedure (SMP) is a documented, step-by-step method for doing a specific maintenance task, such as replacing a bearing or calibrating a sensor, the same safe way every time. It usually lists the tools, parts, safety precautions including lockout points, and the checks that confirm the job was done right. SMPs turn experienced technicians’ know-how into a method others can learn and repeat.

Related: Standard operating procedure (SOP), Lockout/tagout (LOTO), Total productive maintenance (TPM)

Standard operating procedure (SOP)

A standard operating procedure (SOP) is a written, approved document that describes how to carry out a routine operation consistently and safely. It typically states the purpose, scope, responsibilities, required materials, and the steps in order, and it is kept under document control so only the current version is used. On the shop floor, SOPs are often backed by shorter work instructions at each station.

Related: Standard work, Digital work instructions

Standard work

Standard work is the current best known way to do a job, written down with three elements: takt time, the work sequence, and the standard in-process inventory needed to run it. It gives a stable baseline, so abnormalities stand out and improvements can be measured and locked in. Standard work is expected to change as the team finds better methods.

Related: Takt time, Standard operating procedure (SOP), Leader standard work, Standard work in process (SWIP), Standard work audit, Standard work combination table, Job breakdown sheet

Standard work audit

A standard work audit is a periodic check that the written standard for a job matches what happens at the station and is still the best known method. The auditor compares the posted document, the work sequence, cycle times, training records and tools with the standard, then decides for each gap whether the operator drifted from a good standard or the standard itself needs updating, because the two call for opposite fixes. It complements the daily checks in leader standard work.

Related: Standard work, Leader standard work, Layered process audit (LPA), TWI Job Instruction

Standard work combination table

A standard work combination table is a chart of one operator's work elements in sequence, with the manual, machine and walking time of each drawn on a time scale against takt. It shows how the operator's work fits with the machines' automatic cycles, where the operator waits, and whether the cycle fits within takt. It is one of the core standard work documents, with the process capacity sheet and the standard work chart.

Related: Standard work, Takt time, Cycle time, Process capacity sheet, Standard work in process (SWIP)

Standard work in process (SWIP)

Standard work in process (SWIP) is the minimum number of parts that must be inside a process, at and between stations, for operators to follow their standard work sequence without waiting. It is one of the three elements of standard work, with takt time and the work sequence. A common estimate is the total cycle time of the steps ÷ takt time, plus any parts held for curing, cooling, or inspection; anything above the standard is excess inventory.

Related: Standard work, Work in process (WIP), Takt time, Cycle time

Statistical process control (SPC)

Statistical process control (SPC) is the use of statistics, mainly control charts, to monitor a process while it runs and tell normal variation from real change. A control chart plots measurements over time against a center line and control limits, usually set three standard deviations either side of the mean. Points outside the limits or non-random patterns signal a special cause to investigate, while variation inside them is common cause and can only be reduced by changing the process.

Related: Process capability (Cp, Cpk), Six Sigma, Measurement system analysis (MSA), Seven basic quality tools

Stratification

Stratification is the practice of splitting data into groups by its source, such as machine, shift, operator, supplier, or product, before analyzing it. A problem that looks spread evenly across a whole process often turns out to come mostly from one group once the data is separated. It is one of the seven basic quality tools and is usually applied to check sheet, Pareto, and scatter diagram data.

Related: Seven basic quality tools, Check sheet, Pareto analysis, 6Ms of production

Supermarket

In lean, a supermarket is a controlled store of parts placed between two processes that cannot be linked by continuous flow. The downstream process takes what it needs, and the upstream process makes only enough to replace what was taken, usually signaled by kanban. Each item has a fixed location and set minimum and maximum quantities, so the stock level is visible and capped.

Related: Pull system, Kanban, Mizusumashi (water spider)

Supplier audit

A supplier audit is a visit to a supplier’s site to check that the quality system and the process that makes your parts are in place and working, scored against a checklist. A system audit checks the quality management system against a standard such as ISO 9001; a process audit follows a part from receiving through production, inspection and shipping. Audits are done before approving a new supplier, after serious quality problems and on a schedule set by risk, and the findings come back as an action plan with dates.

Related: Supplier scorecard, Supplier corrective action request (SCAR), Layered process audit (LPA), Production part approval process (PPAP)

Supplier corrective action request (SCAR)

A supplier corrective action request (SCAR) is a formal request to a supplier to find and fix the root cause of a problem with what they supplied, such as a rejected lot or a failure traced to their part. It describes the nonconformance and asks for containment, root cause, corrective action and proof that the action worked, often in an 8D format, by set dates. Days to respond and the number of open SCARs are common measures on a supplier scorecard.

Related: Corrective and preventive action (CAPA), 8D problem solving, Non-conformance report (NCR), Supplier scorecard, Incoming inspection

Supplier scorecard

A supplier scorecard is a regular, usually monthly, report card that rates each supplier on the same measures, most often quality (PPM or lot rejection rate), on-time delivery and how quickly corrective action requests are answered. Each measure is scored against a target, weighted and added into one score and rating, so supplier reviews start from data both sides can check. The trend shows which suppliers need development and whether their corrective actions are working.

Related: Parts per million (PPM), On-time delivery (OTD), Supplier corrective action request (SCAR), Supplier audit, Incoming inspection

Takt time

Takt time is the rate at which products must be finished to meet customer demand, calculated as available production time divided by customer demand for that period. For example, 27,000 seconds of available time and demand for 900 units give a takt time of 30 seconds per unit. It sets the pace for the line and is the target that station cycle times are balanced against.

Related: Cycle time, Line balancing, Standard work

Target condition

A target condition is a description of how a process should work at a set date not far off, with the measurable result it should reach. In the improvement kata it sits between the current condition and the longer-term challenge, and the learner experiments toward it one obstacle at a time. It describes the work pattern that should produce the number, not only the number itself.

Related: Coaching kata, PDCA (Plan-Do-Check-Act), A3 problem solving

Team charter

A team charter is a short written agreement, made by a standing team with its sponsor, that sets out the team's purpose, scope, members and roles, the KPIs it owns, the decisions it may make on its own, its norms and its meeting cadence. Unlike a project charter it has no end date: the team reviews it on a set date and whenever its scope or members change.

Related: Project charter, Tiered meetings, Daily huddle, Employee engagement

Theory of constraints (TOC)

The theory of constraints (TOC) is a management approach, developed by Eliyahu Goldratt, that treats the output of any system as limited by its tightest constraint, often a bottleneck machine or process. Improvement follows five focusing steps: identify the constraint, exploit it, subordinate everything else to it, elevate it, and then repeat for the next constraint. Time lost at the constraint is lost for the whole system, so that is where improvement pays back most.

Related: Line balancing, Cycle time, Takt time, Bottleneck, Throughput

Throughput

Throughput is the rate at which a process turns out finished, good output, such as units per hour or orders per day. A line’s throughput is set by its bottleneck, so speeding up other steps does not raise it and only builds inventory. In the theory of constraints, throughput is defined in money terms instead, as the rate at which the system generates money through sales.

Related: Bottleneck, Throughput time, Theory of constraints (TOC), Work in process (WIP)

Throughput time

Throughput time is the total time a unit takes to pass through a process from start to finish, including processing, inspection, moving, and waiting. Because waiting is usually the largest part, it is much longer than the sum of the cycle times, and cutting queues and batch sizes shortens it most. Despite the similar name it is a time, not a rate like throughput, and for a stable process it equals work in process ÷ throughput (Little’s Law).

Related: Lead time, Cycle time, Throughput, Work in process (WIP), Value-added time

Tier board

A tier board is the visual board a team stands at during its tiered meeting, showing that level’s performance against target, usually grouped by SQDCM, along with open problems and their actions. Each tier’s board is fed by the one below it, so an issue can be traced from the front-line board up to the plant leadership board. Red and green marks against each target show in seconds where attention is needed.

Related: Tiered meetings, SQDCM, Hour-by-hour board, Visual management

Tiered meetings

Tiered meetings are a cascade of short stand-up meetings held at set times each day, from front-line teams (tier 1) to area leaders (tier 2) and plant leadership (tier 3 and above). Each tier reviews performance, often by SQDCM, and escalates problems it cannot solve to the next tier, while decisions and support flow back down. The cascade gets each problem to the level that can fix it on the same day.

Related: SQDCM, Leader standard work, Visual management, Tier board, Daily huddle

Total effective equipment performance (TEEP)

Total effective equipment performance (TEEP) measures how much of all calendar time, 24 hours a day, every day of the year, a machine spends making good parts at full speed. It is calculated as OEE × utilization, where utilization is planned production time ÷ all available time. OEE shows how well the scheduled time is used, while TEEP also shows the capacity left in unscheduled shifts, weekends, and planned stops.

Related: Overall equipment effectiveness (OEE), Planned downtime, Six big losses

Total productive maintenance (TPM)

Total productive maintenance (TPM) is a plant-wide approach to equipment reliability that makes operators, maintenance, and management jointly responsible for keeping machines in top condition. It aims for no breakdowns, no small stops or slow running, no defects, and no accidents, and it is usually organized in pillars such as autonomous maintenance, planned maintenance, and focused improvement. OEE is its usual measure of progress.

Related: Autonomous maintenance, Overall equipment effectiveness (OEE), Six big losses, Eight pillars of TPM

Total quality management (TQM)

Total quality management (TQM) is a management approach in which everyone in the organization shares responsibility for quality and for continually improving processes to meet customer needs. Its core principles include customer focus, involvement of all employees, a process view of work, decisions based on data, and continual improvement. Many of its tools, such as quality circles, Pareto analysis, and PDCA, are shared with lean and Six Sigma.

Related: Quality circle, PDCA (Plan-Do-Check-Act), Six Sigma

Toyota Production System (TPS)

The Toyota Production System (TPS) is the production and management system developed at Toyota and the basis of what became known in the West as lean manufacturing. It is often drawn as a house with two pillars, just-in-time and jidoka, standing on a foundation of standardized work, heijunka, stability, and kaizen. Its aim is to make exactly what the customer needs with the least waste, while developing people who solve problems every day.

Related: Just-in-time (JIT), Jidoka, Lean manufacturing

TWI Job Instruction

TWI Job Instruction is a four-step method for teaching someone to do a job correctly, safely, and consistently: prepare the worker, present the operation, try out performance, and follow up. Before training, the trainer writes a job breakdown sheet listing the important steps, the key points, and the reasons for each key point. It comes from the Training Within Industry program created in the United States during World War II and is widely used to teach standard work.

Related: Standard work, Skills matrix, One-point lesson (OPL), Job breakdown sheet

Unplanned downtime

Unplanned downtime is any time a machine or line stops when it was scheduled to run, because of a breakdown, missing material or operators, a quality problem, or another unexpected event. It is the most disruptive kind of stoppage because nothing is ready for it, and in OEE it counts as an availability loss. Reducing it is the main goal of preventive, predictive, and autonomous maintenance.

Related: Planned downtime, Six big losses, Mean time between failures (MTBF), Mean time to repair (MTTR)

Value stream mapping (VSM)

Value stream mapping (VSM) is a lean method for drawing every process step, material flow, and information flow needed to bring a product from order to delivery. The current-state map shows where time is lost and waste sits, usually summarized as total lead time against value-added time; the future-state map shows the target flow and the plan to reach it. It helps teams improve the whole flow instead of optimizing single steps.

Related: 8 wastes of lean (DOWNTIME), Kaizen event, Lead time, Value-added time, Process flow diagram

Value-added time

Value-added time is time spent on steps that change the product in a way the customer is willing to pay for, done right the first time. Non-value-added time is everything else, and it splits into pure waste, which can be removed, and necessary non-value-added work, such as some inspections or regulatory steps, which cannot be removed yet. Comparing value-added time with total lead time shows how much of a process is waiting and handling.

Related: 8 wastes of lean (DOWNTIME), Lead time, Value stream mapping (VSM)

Visual management

Visual management is the practice of making the state of work visible at a glance, so anyone can tell whether things are normal or abnormal without asking. It includes floor markings, shadow boards, labels, andon lights, and performance boards. The point is to prompt fast action on problems, not just to display information.

Related: 5S, Andon, Tiered meetings, Floor marking

Waste walk

A waste walk is a planned walk through a work area with the single purpose of spotting and recording waste, usually using the eight wastes as a checklist. Participants observe the real process, note each example with its location and evidence, and turn what they find into improvement actions with owners. It differs from a general gemba walk by having one narrow focus: finding waste.

Related: 8 wastes of lean (DOWNTIME), Gemba walk, Value-added time, Spaghetti diagram

Weighted decision matrix

A weighted decision matrix compares options against the same criteria: each criterion gets a weight that reflects how much it matters, each option is scored on each criterion, and the weighted scores are added up to rank the options. Agreeing the criteria and weights before scoring keeps the result from being steered toward a favorite. Many teams add pass or fail must-haves that rule an option out whatever its total.

Related: Prioritization matrix, Cost-benefit analysis

Work in process (WIP)

Work in process (WIP) is material that has entered a production process but is not yet finished, such as parts waiting between stations, sitting in queues, or partly assembled. Lean treats excess WIP as inventory waste, because it ties up cash and floor space, hides problems, and lengthens lead time. By Little’s Law, average lead time equals average WIP ÷ throughput, so cutting WIP at the same output shortens lead time.

Related: Standard work in process (SWIP), 8 wastes of lean (DOWNTIME), Lead time, One-piece flow, Kanban, Throughput

Work order

In maintenance, a work order is the record that authorizes and describes a job: what needs doing, on which asset, by whom, by when, and with what parts and safety steps. It is raised from a breakdown, an inspection finding, or a preventive maintenance schedule, and it is closed with the work done, the time spent, and the parts used. Closed work orders build the repair history used to calculate MTBF and MTTR and to plan future maintenance.

Related: Computerized maintenance management system (CMMS), F-tag, Preventive maintenance (PM), Mean time to repair (MTTR)

World class manufacturing (WCM)

World class manufacturing (WCM) is a structured production system that combines lean, TPM, and total quality methods and aims for zero accidents, zero defects, zero breakdowns, and zero waste. It is built on ten technical pillars: safety and health, cost deployment, focused improvement, autonomous activities, professional maintenance, quality control, logistics, early equipment management, people development, and environment. Its hallmark is cost deployment, which puts a money value on losses so improvement work goes where the cost is highest.

Related: Eight pillars of TPM, Operational excellence, Cost of poor quality (COPQ)

X-matrix

An X-matrix is a one-page hoshin kanri planning tool that links long-term breakthrough objectives, annual objectives, top-level improvement priorities, and the metrics used to track them, with the people responsible shown alongside. The four lists sit around a central X, and grids in the corners mark which items support which. It lets leaders check that every improvement project traces back to a strategic goal.

Related: Hoshin kanri, Catchball, Bowling chart

Yamazumi chart

A yamazumi chart is a stacked bar chart of the work content at each operator or station, broken into individual tasks and often colored by value-added, non-value-added, and waste. Drawn against a line for takt time, it shows at a glance which stations are overloaded or underused. Yamazumi means “stack up” in Japanese, and the chart is the standard tool for line balancing.

Related: Line balancing, Takt time

Yokoten

Yokoten is the practice of sharing a proven improvement or lesson learned sideways, across lines, shifts, and sites, so other teams can adopt and adapt it. The Japanese word roughly means “horizontal deployment.” Unlike a top-down mandate, the receiving teams go and see the original improvement and then fit it to their own conditions.

Related: Kaizen, Standard work, Jishuken

Zero breakdowns (five countermeasures)

Zero breakdowns is the TPM aim of eliminating equipment breakdowns with five countermeasures: maintain basic conditions (cleaning, lubrication, tightening), keep to operating conditions, restore deterioration, correct design weaknesses and improve operating and maintenance skills. Each countermeasure answers one cause of breakdowns, so a breakdown analysis that names the missing one points straight at the fix.

Related: Total productive maintenance (TPM), Autonomous maintenance, CILR (clean, inspect, lubricate, retighten), Breakdown analysis